SANTA CLARA, Calif.—Randy Moss has been averaging 20 snaps a game, and San Francisco 49ers coach Jim Harbaugh doesn’t see that changing as long as all of his receivers are healthy.

The issue isn’t Moss’ stamina. He’s in excellent shape and hasn’t missed a single practice since April 30. The reason Moss has been in for roughly one-third of the 49ers’ plays this year has to do with the ever-changing personnel packages Harbaugh likes to use.

49ers report: Randy Moss is getting on the field for about 20 snaps a game. (AP Photo)

The 49ers activate five wideouts on game days, and all five have a role in the offense. In fact, Moss has seen the fourth-most snaps among wideouts this season, behind Michael Crabtree, Mario Manningham and Kyle Williams. (Ted Ginn has been injured and returned to the lineup Sunday.)

Moss isn’t part of the team’s base package in which Crabtree and Manningham are the wideouts. He also remains on the sideline in three-receiver sets, which feature Williams, who is very quick and who plays out of the slot.

Moss enters the game opposite Crabtree in some offensive formations. He also is the lone wideout in some run-based formations because he draws attention from the cornerback and the safety, thereby making it easier for the 49ers to run the ball. An injury to one of the starters, Crabtree or Manningham, likely would increase Moss’ snaps.

He’s a bigger target and a more dangerous downfield threat than Williams, and he’d likely get the starting nod in that scenario. Moss was targeted only once in Sunday’s win over the Jets—a 58-yard incomplete heave into the end zone from backup quarterback Colin Kaepernick. It was Kaepernick’s only pass of the day.